A recent paper by Weizmann Institute scientists suggests that we might be able to break the third law of thermodynamics. This is how that law was originally formulated in 1908 by Walther Nernst: “It is impossible for any procedure to lead to the isotherm T = 0 in a finite number of steps,” (source: Wikipedia). To elaborate, the entropy of a system approaches nil as the temperature closes in on absolute zero, so that extracting further energy becomes increasingly difficult. According to the third law, you can get very close – temperatures of less than a billionth of a degree have already been achieved – but you can never get all the way there. Another way to think of it is in terms of classical cooling: We chill things by drawing heat (energy) from a warmer source to a colder one. But at temperatures nearing absolute zero, where do you find something even more frigid to draw out that last bit of heat?
Prof. Gershon Kurizki and research student David Gelbwaser-Klimovsky proposed a plan for moving energy in the opposite direction – from cold to hot. This totally non-intuitive plan relies on some strange and surprising aspects of quantum mechanics that Kurizki and his group had previously discovered: Frequent measurement in a quantum system – for example, a single atom – can affect the heat exchange between the atom and its surroundings that would normally lead to equilibrium. This part was demonstrated several years ago in an experiment by a different Weizmann group.
Kurizki now has an idea of how experimental physicists might be able to attain absolute zero in a chain of spins connected to a quantum refrigerator made of a single atom, two “heat baths” – hot and cold – for heat exchange and an oscillator for the energy transfer. He admits that if the third law is eventually proved fallible in an experiment, it could create problems for more than one physics theory. “But that is ultimately what drives science – surprises and debate,” he says.
Check out our other new stories, as well:
A strange material, in which a conducting layer magically appears between two insulators, just got even stranger,
Family affair: Swiss father and son researchers Drs. Harry and Benjamin Towbin at the Weizmann Institute,
The 2014 edition of the Poetry of Science, including creative writing by scientists.
Also, this lecture by Mario Livio at the Weizmann Institute